It’s called App Store Connect.
The developer-only app can be used to monitor sales trends, receive alerts from user reviews, as well as respond to customer reviews immediately from an iPhone, iPad and iPod touch.
A developer can easily view reviews from all territories, and respond to them using their pocket computer. Previously, they would have to find a computer and load the iTunes Connect website to make any change. Adding custom sales reports is unsupported at the moment.
The app requires a developer account and iOS 11.3 to use.
Keep in mind that the App Store Connect app does not replace Apple’s existing iTunes Connect app for iOS, which lets app and iTune Store media providers see their sales trends and access the media items they have made available for download from Apple’s content stores.